Rollover prevention apparatus

ABSTRACT

The rollover prevention apparatus defines an adaptive steering range limiting device comprising a control unit and a pair of opposing unidirectional brake assemblies mounted to a steering column position detection disc. The rollover prevention apparatus prevents the steering wheel of the vehicle from being turned beyond the threshold of vehicle rollover, but otherwise does not restrict the rotational range of motion of the steering wheel of a vehicle.

CROSS REFERENCE TO RELATED APPLICATIONS

This nonprovisional utility patent application claims the benefit under 35 U.S.C. §119(e) of U.S. provisional application No. 61/378,482 filed Aug. 31, 2010 and of U.S. provisional application No. 61/385,535 filed Sep. 22, 2010 both of which are incorporated, in their entirety, by this reference.

FIELD OF THE INVENTION

The present invention relates to steering control devices and more especially devices for use in preventing steering to the point of vehicle rollover.

BACKGROUND OF THE INVENTION

Vehicle rollover—generally defined as vehicular accident in which a vehicle turns over on its side or roof—is an extremely dangerous form of a vehicle crash. Vehicle rollover accidents while relatively rare—estimated at approximately 3% of all vehicle crashes—account for a disproportionately high number of fatal crashes—estimated at approximately 31% of all fatal vehicle crashes. The Nation Highway Transportation Safety Administration (NHTSA) reported that 10,666 people were killed in the US in vehicle rollover crashes in 2002. Many factors are involved in a vehicle rollover including for instance vehicle center of gravity, vehicle suspension stiffness, vehicle tire traction, etc. However, according to Wikipedia, “The main cause for rolling over is turning too sharply while moving too fast” (see Appendix A, page 1, first paragraph). While there may be several factors for a vehicle to be turned or steered beyond the vehicle threshold of roll such as driver hurry or impatience and driver inexperience, a well know cause for excessive turning or steering to the point of vehicle roll is the occurrence of an object such as a tumble weed or squirrel suddenly appearing in the drivers path (hereafter referred to Sudden Object Appearance or SOA). In such SOA, even the most experienced drivers can feel the inherent and immediate urge to rapidly turn the steering wheel. It is just such turning of the steering wheel that causes many vehicle rollovers.

In recent years, a system commonly referred to as Electronic Stability Control or ESC has, by automatically selectively apply torque or braking force to certain of a vehicles wheels, been used in significantly improving stability of vehicles, especially when such vehicles would have otherwise “spun out” or “fish-tailed” when cornering. However, such ESC systems, which typically require complex rollover prediction schemes, cannot prevent vehicle rollover when a vehicle steering wheel is turned too sharply for the vehicle speed as in a SOA situation. Further, a number of inventions dealing with vehicle steering control have been developed over the years. However, such inventions have typically merely dealt with preventing damage to a driving surface (i.e. turf) or prevention of a power steering system, and no such systems are known to prevent vehicle rollover, especially in a SOA situation. Examples of such inventions are provided in the following list of US patents and applications, the whole of which are incorporated herein by reference: U.S. Pat. Nos. 5,489,006, 6,584,388, 6,588,799, 6,714,848, 6,954,140, 7,107,136, 7,261,303, 7,325,644, 7,440,844, 7613,555, 20030055549, 20030088349, 20030093201, 20040102894, 20040104066, 20040215384, 20050060069, 20050110227, 20060030991, 20060129298, 20060162987, 20070299583, 20080133101, 20090228173, 20100191423, and 20110060505.

SUMMARY OF THE INVENTION

The present invention is a vehicle rollover prevention apparatus. In a first embodiment, the apparatus defines an adaptive steering range limiting device (ASRLD) comprising a control unit and a pair of opposing unidirectional brake assemblies mounted to a steering column position detection disc (SCPDD). The unidirectional brake assemblies comprise a first left hand unidirectional brake assembly (LHUBA) and a second right hand unidirectional brake assembly (RHUBA), with the LHUBA operable to brake in a left hand or counterclockwise (CCW) direction and yet roll substantially freely in a right hand or clockwise (CW) direction, and with the RHUBA operable to brake in a right hand or clockwise (CW) direction and yet roll substantially freely in a left hand or counterclockwise (CCW) direction. The SCPDD includes at least one and preferably a plurality of sensors that sense the angular position of a vehicle steering wheel and provide such angular position information to the control unit. The control unit also receives speed data from a vehicle speed sensor. In practice, when a vehicle in which the ASRLD is installed is moving at less than a predetermined rate of speed, the unidirectional brake assemblies are not applied, and the vehicle steering wheel may be turned to the full hand range of steering motion. However, when a vehicle in which the ASRLD is installed is moving at no less than a predetermined rate of speed and the vehicle steering wheel is turned to no less than a predetermined left hand angle, the LHUBA is automatically applied, and the vehicle steering left hand range of motion is restricted such that the steering wheel may not be turned beyond the threshold of left hand rollover for the particular vehicle for the given vehicle speed. When the vehicle speed and/or steering wheel left hand angle is reduced, the LHUBA is automatically released. Further, when a vehicle in which the ASRLD is installed is moving at no less than a predetermined rate of speed and the vehicle steering wheel is turned to no less than a predetermined right hand angle, the RHUBA is automatically applied, and the vehicle steering right hand range of motion is restricted such that the steering wheel may not be turned beyond the threshold of right hand rollover for the particular vehicle for the given vehicle speed. When the vehicle speed and/or steering wheel right hand angle is reduced, the RHUBA is automatically released. It is noted that when the unidirectional brake assemblies are (separately) applied, although the steering wheel is prevented from being turn beyond a predetermined left hand or right hand angle, the steering wheel is free to be turned back toward a steering wheel centered or neutral position. In this method, a vehicle is prevented from being steered beyond the threshold of vehicle role and yet the vehicle steering wheel remains otherwise usable over the unrestrained rotational range of travel.

DESCRIPTION OF DRAWINGS

In order that the advantages of the invention will be readily understood, a more particular description of the invention briefly described above will be rendered by reference to specific embodiments that are illustrated in the appended drawings. Understanding that these drawings depict only typical embodiments of the invention and are not therefore to be considered to be limiting of its scope, the invention will be described and explained with additional specificity and detail through the use of the accompanying drawings, in which:

FIG. 1 is a trimetric view of a first embodiment of the invention;

FIG. 2 is an orthographic cross-sectional view of the first embodiment of the invention taken substantially at the location indicated by the cross-section arrows annotated with “2” in FIG. 1;

FIG. 3A is an orthographic cross-sectional view of the first embodiment of the invention taken substantially at the location indicated by the cross-section arrows annotated with “3” in FIG. 2, the invention is shown with the LHUBA in an unactuated or open position;

FIG. 3B is an orthographic cross-sectional view of the first embodiment of the invention taken substantially at the location indicated by the cross-section arrows annotated with “3” in FIG. 2, the invention is shown with the LHUBA in an actuated or closed position;

FIG. 4A is an orthographic cross-sectional view of the first embodiment of the invention taken substantially at the location indicated by the cross-section arrows annotated with “4” in FIG. 2, the invention is shown with the RHUBA in an unactuated or open position;

FIG. 4B is an orthographic cross-sectional view of the first embodiment of the invention taken substantially at the location indicated by the cross-section arrows annotated with “4” in FIG. 2, the invention is shown with the RHUBA in an actuated or closed position;

FIG. 5 is a trimetric view of a fourth embodiment of the invention;

FIG. 6A is an orthographic cross-sectional view of the fourth embodiment of the invention taken substantially at the location indicated by the cross-section arrows annotated with “6” in FIG. 5;

FIG. 6B is substantially similar to FIG. 6A except that a first set of actuator pins are shown as extended;

FIG. 6C is substantially similar to FIG. 6A except that a second set of actuator pins are shown as extended;

FIG. 6D is substantially similar to FIG. 6A except that a third set of actuator pins are shown as extended;

FIG. 6E is substantially similar to FIG. 6D except that SCDD 140 is shown rotated to the limit of its right hand rotational range of motion;

FIG. 7 is an orthographic cross-sectional view of the fourth embodiment of the invention taken substantially at the location indicated by the cross-section arrows annotated with “7” in FIG. 6D, with the invention shown without an actuation pin 144 blocking rotational motion of SCDD 140, and;

FIG. 7A is an orthographic cross-sectional view of the fourth embodiment of the invention taken substantially at the location indicated by the cross-section arrows annotated with “7 ” in FIG. 6E, with the invention shown with an actuation pin 144 a blocking rotational motion of SCDD 140.

DETAILED DESCRIPTION OF THE INVENTION

Reference throughout this specification to “one embodiment,” “an embodiment,” or similar language means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment of the present invention. Thus, appearances of the phrases “in one embodiment,” “in an embodiment,” and similar language throughout this specification may, but do not necessarily, all refer to the same embodiment.

Furthermore, the described features, structures, or characteristics of the invention may be combined in any suitable manner in one or more embodiments. In the following description, numerous specific details are included to provide a thorough understanding of embodiments of the invention. One skilled in the relevant art will recognize, however, that the invention can be practiced without one or more of the specific details, or with other methods, components, materials, and so forth. In other instances, well-known structures, materials, or operations are not shown or described in detail to avoid obscuring aspects of the invention.

In order to facilitate the understanding of the present invention in reviewing the drawings accompanying the specification, a feature table is provided below. It is noted that like features are like numbered throughout all of the figures.

FEATURE TABLE # Feature 10 adaptive steering range limiting device 20 steering wheel 30 steering column 40 steering column position detection disc 42 disc 44 magnetic target 50 unidirectional brake assemblies 60 left hand unidirectional brake assembly 62 caliper housing 64 unidirectional roller 70 right hand unidirectional brake assembly 72 caliper housing 74 unidirectional roller 80 electronic control unit 85 sensor 92 left hand or CCW direction indication arrow 94 right hand or CW direction indication arrow 110 adaptive steering range limiting device 120 steering wheel 130 steering column 140 steering column disc device 142 disc 144 actuator pin 144a actuator pin-extended 180 electronic control unit 185 block 192 left hand or CCW direction indication arrow 194 right hand or CW direction indication arrow

Referring now to FIGS. 1 through 4 of the drawings, a first embodiment of the invention is an adaptive steering range limiting device (ASRLD) 10 comprising a steering wheel 20, a steering column 30, a steering column position detection disc (SCPDD) 40, a pair of opposing unidirectional brake assemblies 50, an electronic control unit 80 and a sensor 85. Furthermore arrow 92 defines a left hand or counterclockwise (CCW) direction indication arrow and arrow 94 defines a right hand or clockwise (CW) direction indication arrow. Steering wheel 20 defines a conventional steering wheel as may commonly be found in a commercially available passenger vehicle. Steering column 30 defines a conventional steering column that serves to transmit steering torque from steering wheel 20 to a rack and pinion or other such vehicle wheel control device. SCPDD 40 defines a substantially thin preferably aluminum cylinder shaped disc 42 having a plurality of magnetic targets 44 embedded within disc 42 and spaced substantially equally about the periphery of disc 42. Unidirectional brake assemblies 50 define an assembly comprising a left hand unidirectional brake assembly (LHUBA) 60 and a right hand unidirectional brake assembly (RHUBA) 70. LHUBA 60 defines a brake assembly having a caliper housing 62, and a plurality of actuatable or extendable and retractable unidirectional rollers 64. Unidirectional roller 64 preferably comprises a generally hard rubber roller mounted on at least one unidirectional bearing. Unidirectional bearings are well known in the art and are for instance taught in U.S. Pat. Nos. 3,805,932 and 5,547,055, which are incorporated herein by reference. RHUBA 70 defines a brake assembly having a caliper housing 72, and a plurality of actuatable or extendable and retractable unidirectional rollers 74. Unidirectional roller 74 preferably comprises a generally hard rubber roller mounted on at least one unidirectional bearing. Electronic control unit 80 defines an electronic control unit such as are commonly in use in automobiles, and is adapted to electronically receive speed, position and other sensor input and is adapted to electronically transmit actuation signals based on predetermined inputs. Sensor 85 preferably defines an electronic sensor such as reed switch type sensor that is operable to detect near proximity to magnetic targets 44, and thus is operable to detect rotational positioning of SCPDD 40.

ASRLD 10 is assembled such that steering column 30 is connected to steering wheel 20 on a first end of steering column 30 and to SCPDD 40 on a second end of steering column 30. Unidirectional brake assemblies 50 are positioned near SCPDD 40 such that disc 42 may rotatingly pass between rollers 64 and between rollers 74. Electronic control unit 80 is electronically connected to unidirectional brake assemblies 50 and electronically connected to sensor 85. ASRLD 10 is mounted in a vehicle such that second end of steering column 30 is steeringly connected to a rack and pinion or like steering mechanism of the vehicle such that ASRLD 10 is operable to steer the vehicle. Unidirectional brake assemblies 50 are further connected to a structural member of the vehicle such that unidirectional brake assemblies 50 remain stationary relative to a rotation movement of SCPDD 40 and such that unidirectional brake assemblies 50 are able to react or withstand a steering stopping load. Electronic control unit 80 is further connected to a structural member of the vehicle such that electronic control unit 80 remains stationary regardless of rotation movement of SCPDD 40. Sensor 85 is further connected to a structural member of the vehicle such that sensor 85 remains stationary relative to a rotation movement of SCPDD 40 and such that sensor 85 is able to detect magnetic targets 44 as magnetic targets 44 move into a near proximity position to sensor 85.

In practice, with ASRLD 10 operably mounted in a vehicle, when the vehicle is moving below a predetermined speed, for instance less than 10 miles per hour (mph), unidirectional brake assemblies 50 are not actuated as shown in FIGS. 3A and 4A, and steering wheel 20 may be freely rotated through its the full rotational range of motion. It is noted that when steering wheel 20 is rotated, SCPDD 40 correspondingly rotates between rollers 64 and between rollers 74 and sensor 85 and electronic control unit 80 monitors the rotational orientation of SCPDD 40. However, when the vehicle is moving at or above a predetermined speed, for instance 10 miles per hour (mph), and SCPDD 40 is sensed at being at or above a left hand rotational orientation of greater than a predetermined amount, for instance 10 degrees CCW from a center or neutral steering position, electronic control unit 80 determines a steering prevention threshold has been achieved and sends an actuation signal to LHUBA 60, and LHUBA 60 actuates by moving unidirectional rollers 64 into unidirectional braking contact with SCPDD 40 as shown in FIG. 3B and steering wheel 20 is prevented from rotating further in a left hand or CCW direction but is free to rotate in a right hand or CW direction. When the vehicle slows to less than the predetermined speed or when steering wheel 20 is rotated to a rotational orientation of below the predetermined amount, LHUBA 60 “deactuates” by moving unidirectional rollers 64 out of braking contact with SCPDD 40 as shown in FIG. 3A, and steering wheel 20 may again be rotated freely in both directions (CCW and CW) unless and until another steering prevention threshold is reached. Further, when the vehicle is moving at or above a predetermined speed, for instance 10 miles per hour (mph), and SCPDD 40 is sensed at being at or above a right hand rotational orientation of greater than a predetermined amount, for instance 10 degrees CW from a center or neutral steering position, electronic control unit 80 determines a steering prevention threshold has been achieved and sends an actuation signal to RHUBA 70, and RHUBA 70 actuates by moving unidirectional rollers 74 into unidirectional braking contact with SCPDD 40 as shown in FIG. 4B and steering wheel 20 is prevented from rotating further in a right hand or CW direction but is free to rotate in a left hand or CCW direction. When the vehicle slows to less than the predetermined speed or when steering wheel 20 is rotated to a rotational orientation of below the predetermined amount, RHUBA 70 “deactuates” by moving unidirectional rollers 74 out of braking contact with SCPDD 40 as shown in FIG. 4A, and steering wheel 20 may again be rotated freely in both directions (CCW and CW) unless and until another steering prevention threshold is reached.

It is noted that ASRLD 10 is preferably adapted such that the various steering prevention thresholds are of substantially fine increments such that the braking of steering wheel 20 is accomplished in a fashion that approximates a smooth non-stair-stepped method. For example, if a vehicle equipped with ASRLD 10 were to be traveling on a substantially large flat horizontal paved surface at a high rate of speed, such as for instance 100 mph, and steering wheel 20 were to be turned hard to the right (or the left), ASRLD 10 would prevent steering wheel 20 from being turned to the right (or the left) to the point that the vehicle would rollover to the left (or to the right), and would more specifically, allow steering wheel 20 to be turned to the right (or the left) very near to but just less than the threshold of vehicle rollover. Further, in the above described scenario, if the right hand (or left hand) steering load were maintained on steering wheel 20 and the vehicle was to be allowed to decelerate, such as by coasting or by braking, the vehicle would turn to the right (or to the left) at an substantially continuously sharper right hand (or left hand) turn (e.g. a substantially decreasing turn radius) corresponding to the decreased rate of speed until the vehicle slowed to the point that it would be traveling at less than the first or slowest steering prevention threshold (such as less than 10 mph). Once the vehicle slowed to the first or slowest steering prevention threshold, the vehicle would then turn to the right (or to the left) at a constant turn rate which would be the full unrestricted turn rate of the vehicle. Thus by this description, it can be seen that at substantially any speed of the vehicle, the vehicle is allowed to turn at a rate approaching but just less than the vehicle rollover threshold for such given “any” speed. ASRLD 10 is somewhat analogous to “anti-lock braking”. With anti-lock braking, braking and vehicle control is maximized (breaking distance minimized) by allowing the brakes to apply a braking force that approaches but is never allowed to exceed the tire-to-ground traction breaking threshold. Analogously, with ASRLD 10, steering and vehicle control is maximized by allowing the vehicle to be steered to a degree that approaches but is never allowed to exceed the vehicle rollover threshold.

It is noted that each vehicle model or alteration thereof may have a different propensity for roll. In the first embodiment, such propensity is predetermined and corresponding combinations of turn degree and vehicle speed are determined for various vehicle rollover thresholds. However, it is also understood that vehicle roll propensity is influenced a plurality of factors. In addition to speed and turn degree, such factors may include for instance vehicle center of gravity, vehicle suspension stiffness, vehicle wheel base width, vehicle loading, vehicle tire pressure, traction between a road and the vehicle tires, road angle/banking, etc. Thus in a second embodiment, the second embodiment is substantially identical to the first embodiment except that in the second embodiment, factors in addition to vehicle speed and turn degree are monitored and rollover thresholds are determined on-the-fly.

It is noted that inasmuch as there may be a belief by some that certain circumstances may exist wherein the likelihood of injury or death may be less if a vehicle is allowed to be steered beyond a vehicle threshold of rollover than if a vehicle is restricted from being steered beyond a vehicle threshold of rollover. To satisfy such potential concerns, in a third embodiment, the third embodiment is substantially identical to the second embodiment except that the third embodiment includes an override mode. In such override mode the steering rotational range of motion is automatically not restricted even if a steering prevention threshold is exceeded if an override logic criterion is satisfied. Such override logic criteria may comprise for instance, the detection of a human in near proximity of the drive path of the vehicle or for instance, the detection of a road surface having less than a predetermined coefficient of friction (e.g. an ice packed road).

Referring now to FIGS. 5 through 7 of the drawings, a fourth embodiment of the invention is an adaptive steering range limiting device (ASRLD) 110 comprising a steering wheel 120, a steering column 130, a steering column disc device (SCDD) 140, an electronic control unit 180 and a block 185. Furthermore arrow 192 defines a left hand or counterclockwise (CCW) direction indication arrow and arrow 194 defines a right hand or clockwise (CW) direction indication arrow. Steering wheel 120 defines a conventional steering wheel as may commonly be found in a commercially available passenger vehicle. Steering column 130 defines a conventional steering column that serves to transmit steering torque from steering wheel 120 to a rack and pinion or other such vehicle wheel control device. SCDD 140 defines a substantially thin preferably aluminum cylinder shaped disc 142 having a plurality of actuator pins 144 affixed to disc 142 and spaced substantially equally about the periphery of disc 142. Actuator pins 144 are mounted to disc 142 such that in an un-actuated or retracted position, actuator pins 144 are positioned substantially flush with disc 142 and such that in an actuated or extended position, actuator pins 144 are positioned substantially in a position so as to potentially interfere with block 185. Electronic control unit 80 defines an electronic control unit such as are commonly in use in automobiles, and is adapted to electronically receive speed input and is adapted to electronically transmit actuation signals based on predetermined inputs. Block 185 preferably defines rigidly fixed preferably metallic block that is connect to a vehicle structural member and does not move with disc 142.

ASRLD 110 is assembled such that steering column 130 is connected to steering wheel 120 on a first end of steering column 130 and to SCDD 140 on a second end of steering column 130. Electronic control unit 180 is electronically connected to actuator pins 144. ASRLD 110 is mounted in a vehicle such that second end of steering column 130 is steeringly connected to a rack and pinion or like steering mechanism of the vehicle such that ASRLD 110 is operable to steer the vehicle. Block 185 is connected to a structural member of the vehicle such that block 185 remains stationary relative to a rotation movement of SCDD 140 and such that block 185 is able to react or withstand a steering stopping load. Electronic control unit 180 is further connected to a structural member of the vehicle such that electronic control unit 180 remains stationary regardless of rotation movement of SCDD 140.

In practice, with ASRLD 110 operably mounted in a vehicle, when the vehicle is moving below a predetermined speed, for instance less than 5 miles per hour (mph), none of actuator pins 144 are actuated as shown in FIGS. 6A and 6, and steering wheel 120 may be freely rotated through its the full (unrestricted) rotational range of motion. It is noted that when steering wheel 120 is rotated, SCDD 140 correspondingly in very near proximity to stationary block 185. However, when the vehicle is moving at or above a first predetermined speed, for instance 10 miles per hour (mph), electronic control unit 80 determines a first steering prevention threshold has been achieved and sends an actuation signal to a first set of actuator pins 144 as shown in FIG. 6B and steering wheel 120 is prevented from rotating beyond a first restricted range of rotational motion. When the vehicle is moving at or above a second predetermined speed, for instance 35 miles per hour (mph), electronic control unit 80 determines a second steering prevention threshold has been achieved and sends an actuation signal to a second set of actuator pins 144 as shown in FIG. 6C and steering wheel 120 is prevented from rotating beyond a second restricted range of rotational motion. When the vehicle is moving at or above a third predetermined speed, for instance 65 miles per hour (mph), electronic control unit 80 determines a third steering prevention threshold has been achieved and sends an actuation signal to a third set of actuator pins 144 as shown in FIG. 6D and steering wheel 120 is prevented from rotating beyond a third restricted range of rotational motion. When the vehicle slows to less than a given predetermined speed threshold, or when a more restrictive set of actuator pins 144 are actuated or extended, electronic control unit 80 sends an retraction signal to a given set of actuator pins 144, and actuator pins 144 “deactuate” or retract and return to their home position, steering wheel 120 may again be rotated freely in both directions (CCW and CW) unless and until another steering prevention threshold is reached. It is noted that in the fourth embodiment of the invention, in contrast to systems that react to initiation of vehicle rollover. ASRLD 110 functions in a “proactive” mode by preventing the vehicle from initiating a rollover.

It is noted that ASRLD 110 is preferably adapted such that the various steering prevention thresholds are of substantially fine increments such that the varying of steering range of motion of steering wheel 120 is accomplished in a fashion that approximates a smooth non-stair-stepped method. For example, if a vehicle equipped with ASRLD 110 were to be traveling on a substantially large flat horizontal paved surface at a high rate of speed, such as for instance 100 mph, and steering wheel 120 were to be turned hard to the right (or the left), ASRLD 110 would prevent steering wheel 120 from being turned to the right (or the left) to the point that the vehicle would rollover to the left (or to the right), and would more specifically, allow steering wheel 120 to be turned to the right (or the left) very near to but just less than the threshold of vehicle rollover. Further, in the above described scenario, if the right hand (or left hand) steering load were maintained on steering wheel 120 and the vehicle was to be allowed to decelerate, such as by coasting or by braking, the vehicle would turn to the right (or to the left) at an substantially continuously sharper right hand (or left hand) turn (e.g. a substantially decreasing turn radius) corresponding to the decreased rate of speed until the vehicle slowed to the point that it would be traveling at less than the first or slowest steering prevention threshold (such as less than 10 mph). Once the vehicle slowed to the first or slowest steering prevention threshold, the vehicle would then turn to the right (or to the left) at a constant turn rate which would be the full unrestricted turn rate of the vehicle. Thus by this description, it can be seen that at substantially any speed of the vehicle, the vehicle is allowed to turn at a rate approaching but just less than the vehicle rollover threshold for such given “any” speed. ASRLD 110 is somewhat analogous to “anti-lock braking”. With anti-lock braking, braking and vehicle control is maximized (breaking distance minimized) by allowing the brakes to apply a braking force that approaches but is never allowed to exceed the tire-to-ground traction breaking threshold. Analogously, with ASRLD 110, steering and vehicle control is maximized by allowing the vehicle to be steered to a degree that approaches but is never allowed to exceed the vehicle rollover threshold. 

What is claimed is:
 1. A rollover prevention apparatus that allows a vehicle to be steered within a non-rollover steering range of motion of said vehicle but prevents said vehicle from being steered beyond a rollover threshold of said vehicle.
 2. The apparatus of claim 1, wherein said apparatus prevents said vehicle from being steered to the point of vehicle rollover.
 3. The apparatus of claim 1, wherein said apparatus is automatically actuated in response to the speed of said vehicle.
 4. The apparatus of claim 1, wherein said apparatus prevents said vehicle from being steered to the point of vehicle rollover in a first direction but allows said vehicle to be freely steered in a second direction.
 5. The apparatus of claim 1, wherein said apparatus includes at least one unidirectional brake operatively and adaptively mounted to a steering member such that said vehicle may be freely steered in response to a first condition, and such that said vehicle is automatically prevented from being steered in at least one direction in response to a second condition.
 6. The apparatus of claim 5, wherein said first condition defines a combination of vehicle speed and degree of steering position that substantially does not approach a vehicle rollover threshold, and wherein said second condition defines a combination of vehicle speed and degree of steering position that substantially approaches a vehicle rollover threshold.
 7. The apparatus of claim 5, wherein said first condition defines a combination of rollover factors that do not substantially approach a vehicle rollover threshold, said factors comprising vehicle speed, degree of steering position, vehicle center of gravity, vehicle suspension stiffness, vehicle wheel base width, vehicle loading, vehicle tire pressure, traction between a road and vehicle tires, and road bank angle, and wherein said second condition defines a combination of rollover factors that substantially approach a vehicle rollover threshold, said factors comprising vehicle speed, degree of steering position, vehicle center of gravity, vehicle suspension stiffness, vehicle wheel base width, vehicle loading, vehicle tire pressure, fraction between a road and vehicle tires, and road bank angle.
 8. The apparatus of claim 6, wherein said at least one direction defines a direction that increased steering of said vehicle in said at least one direction would cause said vehicle to rollover.
 9. A steering range of motion control apparatus defining at least one unidirectional control device, wherein said at least one unidirectional control device is automatically applied when a vehicle's steering approaches a rollover threshold of said vehicle.
 10. The steering range of motion control apparatus of claim 9, wherein said apparatus automatically prevents a vehicle from being steered beyond a threshold of rollover of said vehicle.
 11. The steering range of motion control apparatus of claim 9, wherein said unidirectional control device defines a unidirectional brake, and wherein when said unidirectional brake is applied, a steering wheel of said vehicle is allowed to be rotated in a first direction but is prevented from being rotated in a second direction.
 12. The apparatus of claim 9, wherein said rollover threshold is automatically determined based upon a combination of vehicle speed and degree of steering position.
 13. The apparatus of claim 9, wherein said rollover threshold is automatically determined based upon a combination of vehicle speed, degree of steering position, vehicle center of gravity, vehicle suspension stiffness, vehicle wheel base width, vehicle loading, vehicle tire pressure, traction between a road and vehicle tires, and road bank angle.
 14. An adaptive steering apparatus that automatically adaptively prevents a vehicle from being steered beyond the threshold of roll of said vehicle at any speed of said vehicle while also providing for maximal non-rollover steering range of motion of said vehicle, wherein said apparatus that automatically adjusts a steering range of motion in response to at least one predetermined input.
 15. The apparatus of claim 14, wherein said adaptively adjusted steering range of motion defines a steering range of motion that does not exceed a vehicle rollover threshold.
 16. The apparatus of claim 14, wherein said apparatus adjusts in response to vehicle speed.
 17. The apparatus of claim 16, wherein said adaptively adjusted steering range of motion defines a steering range of motion that is inversely proportional to vehicle speed.
 18. The apparatus of claim 14, wherein said apparatus adjusts in response to at least one of vehicle speed, degree of steering position, vehicle center of gravity, vehicle suspension stiffness, vehicle wheel base width, vehicle loading, vehicle tire pressure, fraction between a road and vehicle tires, and road bank angle.
 19. The apparatus of claim 14, wherein said apparatus includes a unidirectional motion control device.
 20. The apparatus of claim 19, wherein said unidirectional motion control device defines a unidirectional brake, and wherein when said unidirectional brake is applied, a steering wheel of a vehicle is allowed to be rotated in a first direction but is prevented from being rotated in a second direction.
 21. An adaptive steering apparatus for use in automatically adaptively preventing a vehicle from being steered beyond the threshold of roll of said vehicle at any speed of said vehicle while also providing for maximal non-rollover steering range of motion of said vehicle at any speed of said vehicle, wherein said apparatus automatically and adaptively adjusts the steerable range of motion of a vehicle such that said steerable range of motion does not exceed the rollover threshold of said vehicle at substantially any speed of said vehicle.
 22. The apparatus of claim 21, wherein said apparatus adjusts in response to at least one input comprising vehicle speed, degree of steering position, vehicle center of gravity, vehicle suspension stiffness, vehicle wheel base width, vehicle loading, vehicle tire pressure, traction between a road and vehicle tires, and road bank angle. 